Method, system and device for adaptive modulation and coding

ABSTRACT

An adaptive modulation and coding method is provided by the present invention, comprising: selecting punctured Physical Resource Blocks (PRBs) to transmit the downlink data for the User Equipment (UE); determining the Transport Block Size (TBS) and the number of punctured PRB pairs for transmission to the UE based on the carried service; scheduling the downlink data for the UE based on the determined TBS, and transmitting the number of the used punctured PRB pairs and a Modulation and Coding Scheme (MCS) sequence number to the UE; and the UE converting the number of the punctured PRB pairs to the number of normal PRB pairs, determining the modulation scheme and the TBS sequence number based on the MCS sequence number, and determining the TBS of the downlink data based on the number of the normal PRB pairs and the TBS sequence number. The specific condition when downlink data are transmitted with punctured PRBs may be performed in the present invention on the basis of utilizing the existing resources and adaptive processing of the general subframes by performing conversion between the number of punctured PRBs and the number of normal PRBs in scheduling resource for the UE with the NodeB, which may be implemented simply and efficiently.

FIELD OF THE INVENTION

The invention relates to the domain of mobile communication technology,in particular to a method, a system and a device for an adaptivemodulation and coding.

BACKGROUND OF THE INVENTION

The Third Generation Wireless Communication (3G) system utilizes CDMA(Code-Division Multiple Access) mode, supports multimedia services, andwill have higher competitive ability for the coming several years.However, the 3GPP (Third Generation Partnership Project) started theresearch project of LTE (Long Term Evolution) for 3G wireless interfacetechnology in order to keep this competitive ability for a longer timein the future. And AMC (Adaptive Modulation and Coding) technology hasbecome one of key technologies of LTE.

AMC (Adaptive Modulation and Coding) technology is a physical layer linkadaptation technology which can compensate the influence of fading onthe signal reception due to channel variation by means of adaptivelyadjusting the modulation and coding mode of transmitting data, so as toimprove the signal-to-noise ratio performance of the signal. AMC isrealized as follows: the system establishes a Modulation and CodingScheme (MCS) of transmission according to the physical layer ability andthe channel quality, the MCS including parameters, such as the codingrate and modulation scheme for transmitting data, in which the systemwill choose different transmission modulation scheme and/or channelcoding rate corresponding to the channel conditions to match thevariable channel condition. In order to better understand the presentinvention, some basic technologies used in the present invention will bebriefly introduced.

Currently, it is ensured that the LTE system supports two framestructures, namely a first type frame structure suitable for FDD(Frequency Division Duplex) system, and a second type frame structuresuitable for TDD (Time Division Duplex) system. For better understandingof the present invention, the first and second type frame structure willbe simply illustrated hereafter.

As shown in FIG. 1, it is a schematic view of the first type framestructure of FDD system in the prior art. The first type wireless framehas a length of 10 ms and consists of 20 time slots, each slot having alength of 0.5 ms, being denoted from 0 to 19. Two continuous time slotsare defined as one subframe, and the subframe i consists of time slot 2i and 2 i+1, wherein i=0, 1, . . . , 9.

As shown in FIG. 2, it is a schematic view of the second type framestructure of TDD system in the prior art. The second type wireless framealso has a length of 10 ms and is firstly split into two half-frames of5 ms. Each half-frame is divided into five subframes of 1 ms. Accordingto the specific configuration of time slot proportion, subframe 1 andsubframe 6 may be configured as special service subframe and consists ofthree special time slots (downlink pilot DwPTS, guard interval GP anduplink pilot UpPTS). DwPTS, as well as a general downlink subframe, canbe used to carry downlink service data.

In LTE (long term evolution) system, MCS is designed based on PRB(Physical Resource Block) structure of general subframe, and then AMCprocess is realized by means of checking TBS (transport Block Size)table. Wherein, PRB is a basic unit for resource scheduling of LTE. Asshown in FIG. 3, it schematically illustrates PRB and RE in uplink timeslot in the prior art, to which PRB and RE in downlink time slot issimilar. Wherein, the minimum resource granularity determined by a timedomain OFDM (Orthogonal Frequency Division Multiplexing) symbol andfrequency domain sub-carrier is called RE (resource element). Currently,the normal PRB of a general subframe is defined as a time-frequencyresource granularity with time domain of 0.5 ms and frequency domain of180 kHz in the protocol, i.e., the time domain corresponds to 7 OFDMsymbols (for normal CP) or 6 OFDM symbols (for extended CP) and thefrequency domain corresponds to one time-frequency resource granularityof 12 sub-carriers.

However, in LTE system, there may be some punctured PRB resources insome special service subframe, such as DwPTS in the special servicesubframe of TDD system (as shown in FIG. 2), or punctured PRB owing tosynchronization channel, broadcast channel etc. The punctured PRB inthese special service subframes can be used to carry downlink data as anormal PRB in general subframe. However, as the existing TBS table isdesigned based on a normal PRB, most of which can not be directlyapplied to the punctured PRB.

The disadvantage of the prior art is in that: most of options are notadapted to the punctured PRB as the TBS table defined by the existingprotocol is designed based on the normal PRB. If no amendment is made,then it will result in that it is impossible for the punctured PRB tochoose the optimum transmission format according to channel quality, andthe efficiency of spectrum transmission will be lowered.

For further understanding of the above defects in the prior art, AMC inthe prior art will be briefly described as an example. However, itshould be known that the hereinafter mentioned punctured PRB is only oneinstance in the prior art instead of representing all instances ofpunctured PRB in the prior art. Firstly, MCS design is implemented basedon PRB structure of general subframe. For the LTE system, servicechannel now supports three modulation schemes of QPSK, 16QAM and 64QAM.These three modulation schemes cooperate with specific coding rate toobtain 29 MCSs, and 3 MCSs are reserved to impliedly map TBS andmodulation scheme during re-transmission, thereby there are 32 optionsof MCS altogether, which can be indicated by 5 bits. The system selectsthe optimum modulation scheme and channel coding rate to transmit dataaccording to the measurement and prediction of channel, so as to realizethe maximum system throughput while ensuring a certain transmissionquality. The detailed indication for MCS can be conducted with referenceto the following table 1 and 2.

TABLE 1 list of the modulation scheme and TBS sequence numbercorresponding to the MCS sequence number MCS sequence TBS sequencenumber I_(MCS) modulation scheme Q_(m) number I_(TBS) 0 2 0 1 2 1 2 2 23 2 3 4 2 4 5 2 5 6 2 6 7 2 7 8 2 8 9 2 9 10 4 9 11 4 10 12 4 11 13 4 1214 4 13 15 4 14 16 4 15 17 6 15 18 6 16 19 6 17 20 6 18 21 6 19 22 6 2023 6 21 24 6 22 25 6 23 26 6 24 27 6 25 28 6 26 29 2 reserved 30 4 31 6

Wherein, MCS indication information of 5 bits in the schedulingsignalling indicates the sequence number I_(MCS). According to Table 1,it can be obtained the specific modulation scheme as Q_(m) and thesequence number of TBS as I_(TBS). However, the specific TBS needs to bedetermined by I_(TBS) in combination with the number of occupied PRBN_(PRB). The number of PRB N_(PRB) can be obtained based on resourceindication information of the scheduling signalling, in which thescheduling takes PRB-pair as basic granularity. After I_(TBS) has beenobtained according to table 1, it is also necessary to look up table 2according to I_(TBS) and the number of PRB N_(PRB) to obtain the finalTBS. The size of table 2 is 27×110, but only the portion of N_(PRB) from1 to 9 is illustrated for the sake of clarity.

TABLE 2 TBS table N_(PRB) I_(TBS) 1 2 3 4 5 6 7 8 9 0 16 32 56 88 120152 176 200 232 1 24 48 88 120 160 200 232 272 304 2 32 72 120 160 200248 296 336 376 3 40 104 152 208 272 320 392 440 504 4 48 120 200 264320 408 488 552 632 5 72 152 232 320 424 504 600 680 776 6 320 176 288392 504 600 712 808 936 7 104 232 320 472 584 712 840 968 1096 8 120 248392 536 680 808 968 1096 1256 9 136 296 456 616 776 936 1096 1256 141610 152 320 504 680 872 1032 1224 1384 1544 11 176 376 584 776 1000 11921384 1608 1800 . . . 12 208 440 680 904 1128 1352 1608 1800 2024 13 232488 744 1000 1256 1544 1800 2024 2280 14 264 552 840 1128 1416 1736 19922280 2600 15 280 600 904 1224 1544 1800 2152 2472 2728 16 320 632 9681288 1608 1928 2280 2600 2984 17 336 696 1064 1416 1800 2152 2536 28563240 18 376 776 1160 1544 1992 2344 2792 3112 3624 19 408 840 1288 17362152 2600 2984 3496 3880 20 440 904 1384 1864 2344 2792 3240 3752 413621 488 1000 1480 1992 2472 2984 3496 4008 4584 22 520 1064 1608 21522664 3240 3752 4264 4776 23 552 1128 1736 2280 2856 3496 4008 4584 516024 584 1192 1800 2408 2984 3624 4264 4968 5544 25 616 1256 1864 25363112 3752 4392 5160 5736 26 648 1320 1992 2664 3368 4008 4584 5352 5992

TBS table as shown in the above table 2 is designed based on normal PRBof general service, wherein in order to allow for the factors such asthe system overhead for controlling the signalling and pilot as well asthe extended and normal CP etc., the protocol finally assigns 120 REdownlink to each PRB-pair for carrying data, wherein 120 RE areequivalent to 10 OFDM symbols. Therefore table 2 is not suitable for thepunctured PRB, particularly when more symbols are punctured. If adetermination is made according to table 2, then it will lead todeviation from the actually needed MCS, and thereby resulting indecoding error of UE.

The above defect will be illustrated by the way of examples. It isassumed that UE obtains I_(MCS)=14 and the indicated number of PRB pairis 2 according to downlink scheduling signalling. For general downlinksubframe, the processing of UE is as follows: according to table 1, whenI_(MCS)=14, looking up table 1 to find the corresponding modulationscheme Q_(m)=4, i.e., 16QAM; the sequence number corresponding to TBSI_(TBS)=13; then according to table 2, it is found that TBS=488.Therefore, the practical code rate is generally:(488+24)/(120×4×2)=0.533, i.e., the practical MCS is {16QAM, 0.533}.

However, for DwPTS, it is assumed that DwPTS has a length of 9 OFDMsymbols, then in addition to the overhead for controlling signalling,channel synchronization and pilot, the PRB in the DwPTS which can beused to carry data is approximately 5×12=60 RE. NodeB (base station)will arrange 4 PRB pairs for this UE if it is required to ensureidentical transmission quality, that is, MCS needs to be {16QAM, 0.533}as well and carries 488 data bits. However, UE looks up the TBS tablebased on I_(MCS)=14 and N_(PRB)=4 which is indicated by signalling toobtain 1000 bits rather than 488 bits in fact, this will leads to erroroperation of UE.

Or, during scheduling NodeB considers that actually 488 bits aretransmitted, then the value of TBS which is the most approximate to 488,for example 472, is selected with N_(PRB)=4. Now the correspondingI_(MCS)=7. When NodeB determines the transmission by means of I_(MCS)=7and N_(PRB)=4, this will also result in error operation of UE as UE willbe considered as MCS={QPSK, 1.06} for DwPTS, rather than MCS={16QAM,0.533} which should be obtained. Therefore, for the punctured PRB pairin the above example, MCS {16QAM, 0.533} cannot be realized actually.

SUMMARY OF THE INVENTION

The present invention aims to at least solve the above technicaldefects, in particular using the existing MCS and TBS table to improvespectrum efficiency during AMC by using punctured PRB.

For this purpose, as one aspect, the present invention proposes anadaptive modulation and coding method, comprising the following steps:the base station NodeB selects punctured PRB for the User Equipment (UE)to transmit the downlink data; the NodeB determines the Transport BlockSize (TBS) and the number of punctured PRB pairs for transmission to theUE based on the carried service; the NodeB schedules the downlink datafor the UE based on the determined TBS, and transmits the number of theused punctured PRB pairs and a Modulation and Coding Scheme (MCS)sequence number to the UE; and the UE is used for receiving the downlinkdata transmitted by the NodeB and the number of the used punctured PRBpairs and the MCS sequence number transmitted by the NodeB, andconverting the number of the punctured PRB pairs to the number of normalPRB pairs, determining the modulation scheme and the TBS sequence numberbased on the MCS sequence number, and determining the TBS of thedownlink data based based on the number of the normal PRB pairs and theTBS sequence number.

As another aspect, the present invention also proposes a NodeB,comprising a selection module, a scheduling parameter determinationmodule, a scheduling module, wherein the selection module is used forselecting punctured PRB for the UE to transmit the downlink data; thescheduling parameter determination module is used for determining aTransport Block Size TBS and the number of punctured PRB pairs fortransmission to the UE based on the carried service; the schedulingmodule is used for scheduling the downlink data for the UE based on thedetermined TBS, and transmitting the number of the used punctured PRBpairs and a MCS sequence number to the UE.

The present invention further proposes a UE, comprising a receptionmodule, an indication information obtaining module, a conversion moduleand a TBS determination module, wherein the reception module is used forreceiving the downlink data transmitted through the punctured PRB fromthe NodeB; the indication information obtaining module is used forobtaining the MCS sequence number and the number of the punctured PRBpairs indicated by the scheduling signalling; the conversion module isused for converting the number of the punctured PRB pairs to the numberof normal PRB pairs and the TBS determination module is used fordetermining the modulation scheme and the TBS sequence number based onthe MCS sequence number, as well as determining the TBS of the downlinkdata based on the number of the normal PRB pairs converted by theconversion module and the TBS sequence number.

The present invention further proposes an adaptive modulation and codingmethod, comprising the following steps: a transmitting node selectspunctured PRB and normal PRB to transmit the downlink data; thetransmitting node determines the Transport Block Size (TBS) and thenumber of total PRB pairs for transmission to the receiving node basedon the carried service, the number of total PRB pairs is the summationof the number of the scheduled normal PRB pairs and the number of thescheduled punctured PRB pairs; the transmitting node schedules thedownlink data for the receiving node based on the determined TBS, andtransmits the number of the total used PRB pairs, location informationand a Modulation and Coding Scheme (MCS) sequence number to thereceiving node; the receiving node calculates the number of totalresource based on the number of the total PRB pairs, locationinformation and situation of respective punctured PRBs; the receivingnode calculates the number normal PRB pairs after conversion based onthe number of total resource, determines the TBS of the downlink databased on the calculated number of the normal PRB pairs after conversionand the TBS sequence number determined by the MCS sequence number.

The present invention further proposes an adaptive modulation and codingsystem, comprising a transmitting node and at least one receiving nodeserved by the transmitting node, wherein the transmitting node is usedfor selecting punctured PRBs and normal PRBs to transmit the downlinkdata, and determining the Transport Block Size (TBS) and the number ofthe total PRB pairs for transmission to the receiving node based on thecarried service, the number of the total PRB pairs being the summationof the number of the scheduled normal PRB pairs and the number of thescheduled punctured PRB pairs, and scheduling the downlink data for thereceiving node based on the determined TBS, and transmitting the numberof the total used PRB pairs, location information and a MCS sequencenumber to the receiving node; the receiving node is used for calculatingthe number of total resource based on the number of the total PRB pairs,the location information and the situation of each punctured PRB, andcalculating the number normal PRB pairs after conversion based on thenumber of total resource, and determining the TBS of the downlink databased on the calculated number of the normal PRB pairs after conversionand the TBS sequence number determined by the MCS sequence number.

The present invention further proposes a transmitting node, comprising aselection module, a scheduling parameter determination module, ascheduling module, wherein the selection module is used for selectingpunctured PRB and normal PRB to transmit the downlink data; thescheduling parameter determination module is used for determining theTransport Block Size (TBS) and the number of the total PRB pairs fortransmission to the receiving node based on the carried service, thenumber of the total PRB pairs being the summation of the number of thescheduled normal PRB pairs and the number of the scheduled punctured PRBpairs; the scheduling module is used for scheduling the downlink datafor the receiving node based on the determined TBS, and transmitting thenumber of the total used PRB pairs, location information and a MCSsequence number to the receiving node.

The present invention further proposes a receiving node, comprising areception module, an indication information obtaining module, a normalPRB pair-number calculation module and a TBS determination module,wherein the reception module is used for receiving the downlink datatransmitted through the normal and punctured PRB by the transmittingnode; the indication information obtaining module is used for obtainingthe MCS sequence number and the number of the total PRB pairs indicatedby the scheduling signalling, the number of the total PRB pairs beingthe summation of the number of the scheduled normal PRB pairs and thenumber of the scheduled punctured PRB pairs; the normal PRB pair-numbercalculation module is used for calculating the number of the totalresource based on the number of the total PRB pairs and the situation ofeach punctured PRB, and calculating the number of the normal PRB pairsafter conversion based on the number of total resource; the TBSdetermination module is used for determining the TBS of the downlinkdata based on the calculated number of the normal PRB pairs afterconversion and the TBS sequence number determined by the MCS sequencenumber.

The specific condition when downlink data are transmitted with puncturedPRBs may be performed in the present invention on the basis of utilizingthe existing resources and adaptive processing of the general subframesby performing conversion between the number of punctured PRBs and thenumber of normal PRBs in scheduling resource for the UE with the NodeB,which may be implemented simply and efficiently.

Additional aspects and advantages of the present invention will beillustrated in the following description and part of them will becomeapparent through the following description or be understood through theembodiments of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and/or additional aspects and advantages of the presentinvention will become apparent and easy to be understood through thefollowing description of embodiments in conjunction with accompanyingfigures. Wherein,

FIG. 1 is a schematic view of the first type frame structure of FDDsystem in the prior art;

FIG. 2 is a schematic view of the second type frame structure of TDDsystem in the prior art;

FIG. 3 is a schematic view of PRB and RE in uplink time slot in theprior art;

FIG. 4 schematically shows the locations of primary broadcast channel,secondary synchronization signal and primary synchronization signal inFDD system according to one embodiment of the present invention;

FIG. 5 schematically shows the locations of primary broadcast channel,secondary synchronization signal and primary synchronization signal inTDD system in one embodiment of the present invention;

FIG. 6 is a flowchart of an adaptive modulation and coding methodaccording to the embodiment 1 of the present invention;

FIG. 7 is a structural view of an adaptive modulation and coding systemaccording to the embodiment 1 of the present invention;

FIG. 8 is a flowchart of an adaptive modulation and coding methodaccording to the embodiment 2 of the present invention;

FIG. 9 is a structural view of an adaptive modulation and coding systemaccording to the embodiment 2 of the present invention.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

The embodiments of the present invention will be illustrated in detail.The examples of the embodiments are shown in figures, wherein identicalor similar reference numbers refer to identical or similar featuresthroughout. The following embodiments described with reference tofigures are merely examples and are only used to illustrate the presentinvention rather than being construed as limiting the present invention.

The present invention mainly aims to overcome the technical defect thatit is impossible to realize AMC using punctured PRB in the prior artwith the adaptive processing and resources of the existing generalsubframes through conversion of NodeB and corresponding UE to the numberof PRB pairs without changing the existing {TBS, MCS} tables (such astable 1 and table 2) and without adding new {TBS, MCS} tables to thepunctured PRB. The specific process is briefly introduced as follows:firstly when NodeB schedules resource for UE, if NodeB selects puncturedPRB to transmit downlink data for UE due to quality etc., then it isnecessary for NodeB to covert the number of the normal scheduled PRBpairs N_(PRB) to the number of the punctured PRB pairs N_(P-PRB)according to the size of the punctured PRB as compared to the normalPRB, and to inform the UE of N_(P-PRB) and the related information ofPRB by a scheduling signalling. Wherein, the related information of PRBincludes the specific number of PRBs and corresponding sequence numberwhich carry this transmission. Similarly, UE will covert N_(P-PRB) tothe number of the normal PRB pairs according to N_(P-PRB) and therelated information of PRB in the scheduling signalling so as to look upthe existing {TBS, MCS} table to perform AMC.

It should be further illustrated that, the size of the punctured PRBneeds to be considered (size of normal PRB is already determined) forthe conversion between the number of the normal PRB pairs N_(PRB) andthe number of punctured PRB pairs N_(P-PRB), thus the conversionrelationship between the number of the normal PRB pairs N_(PRB) and thenumber of punctured PRB pairs N_(P-PRB) will vary depending on the sizeof punctured PRB. For example, the normal PRB defined in the protocolcontains 120 REs (or contains 10 OFDM symbols). If the punctured PRBcontains 5 OFDM symbols, then N_(P-PRB)=2 N_(PRB), if the punctured PRBcontains 30 REs, then N_(P-PRB)=2.5 N_(PRB). Thus, it can be seen thatthe conversion relationship between the number of the normal PRB pairsand the number of the punctured PRB pairs varies with change of the sizeof the punctured PRBs. As there are various reasons for producingpunctured PRBs in LTE system, the size of the punctured PRBs aredifferent as well, therefore the conversion relationship between N_(PRB)and N_(P-PRB) cannot be listed exhaustively. Although the presentinvention will make an explanation to the instances for punctured PRBmainly existing in LTE system in the following embodiments, the presentinvention should not be limited to the instances for punctured PRBlisted here, and other instances for punctured PRB should be covered bythe scope of protection of the present invention. In addition, somesimplification may be made during conversion, instead of totallydepending upon the size relationship between the punctured PRB and thenormal PRB. And such kind of conversion should also be covered by thescope of protection of the present invention.

It can be known through the above analysis, the main concept of thepresent invention is to perform AMC by using the existing {TBS, MCS}tables through conversion between N_(PRB) and N_(P-PRB) withoutdesigning new {TBS, MCS} tables necessarily for the punctured PRB. Theconversion relationship between N_(PRB) and N_(P-PRB) will be differentfor different reasons leading to the punctured PRB. Although some maininstances leading to punctured PRB are mentioned in the embodiments ofthe present invention and some corresponding conversion methods areproposed, these are only used for realizing rather than limiting thepresent invention. Therefore, the instances for punctured PRB and thecorresponding conversion relationships not mentioned in the presentinvention but without departing from the above main concept of thepresent invention or based on the above main concept of the presentinvention should also be covered by the scope of protection of thepresent invention.

In order to further understand the following embodiments of the presentinvention, firstly the instances leading to punctured PRB mainlyexisting in the current LTE system and the corresponding size ofpunctured PRB are generalized. However, it is necessary to emphasizeagain that the following listed situations cannot sum up all instancesleading to punctured PRB in the current LTE system, and other instancesleading to punctured PRB are similar to what are listed here. A personskilled in the art could perform similar processing to the otherpunctured instances according to the present invention, thereby theother punctured instances should also be covered by the scope ofprotection of the present invention.

1. Punctured PRB Caused by the Length of DwPTS

TDD system of the current LTE supports various specific service subframeconfiguration, in which DwPTS, Gp and UpPTS take up 1 ms together.However, in different configuration, the length of DwPTS may bedifferent, and, the possible length of DwPTS according to the currentconfiguration includes as follows:

TABLE 3 a list for the length of DwPTS under different specific timeslot configurations DwPTS's length CP length (the number of OFDM symbolsL_(DwPTS)) Normal CP 12 11 10 9 3 Extended 10 9 8 3 CP

According to different configurations of DwPTS's length in the abovetable 3, the overhead for controlling signalling and pilot are soconsidered. The number of OFDM symbols N_(symbol,P-PRB) for puncturedPRB pairs is shown in the following table:

TABLE 4 a list of the number of symbols for punctured PRB pairs Numberof available Type OFDM symbols L_(P-PRB) N_(symbol,P-PRB) normal CP 1 128 normal CP 2 11 7 normal CP 3 10 6 normal CP 4 9 5 normal CP 5 3 —extended CP1 10 8 extended CP2 9 7 extended CP3 8 6 extended CP4 3 —

For example, when DwPTS's length is configured as 12 OFDM symbols intable 3, there will be approximately 8 OFDM symbols available for datatransmission after removing overhead for controlling signalling andpilot, thus N_(symbol,P-PRB)=8. Other instances in table 4 are similarand redundant descriptions will not be repeated.

2. Punctured PRB Caused by the Influence of Broadcast andSynchronization Channel

The influences of broadcast and synchronization channel on FDD systemand TDD system are different, which will be discussed with reference todrawings.

1) FDD System

FIG. 4 schematically shows locations of primary broadcast channel,secondary synchronization signal and primary synchronization signal inFDD system in one embodiment of the present invention. In this figure, anormal CP is taken as an example having a length of 14 OFDM symbols,which is similar to the extended CP and redundant descriptions will notbe repeated. For 72 sub-carriers (equivalent to 6 PRB) between subframe0 and subframe 5 in FDD system, the number of OFDM symbols available fordata transmission is decreased due to the existence of synchronizationchannel or primary broadcast channel. For example, if the controlchannel takes up 2 symbols of resource, the primary broadcast channeltakes up 4 symbols, secondary synchronization signal and primarysynchronization signal each takes up one OFDM symbol, then the number ofOFDM symbols available for data transmission in each PRB is14−2−4−1−1=6. That is, for FDD system, its subframe 0 and subframe 5 arespecific service subframes and their PRBs are punctured.

For FDD system, the number of OFDM symbols L_(P-PRB) available insubframe 0 and subframe 5, as well as the number of OFDM symbolsN_(symbol,P-PRB) corresponding to punctured PRB after considering theoverhead for controlling signalling and pilot are listed as follows:

TABLE 5 a list of the number of symbols N_(symbol,P-PRB) correspondingto punctured PRB in FDD system Number of available Type OFDM symbolsL_(P-PRB) N_(symbol,P-PRB) normal CP subframe 0 8 4 subframe 5 12 8extended subframe 0 6 4 CP subframe 5 10 82) TDD System

FIG. 5 schematically shows locations of primary broadcast channel,secondary synchronization signal and primary synchronization signal inTDD system in one embodiment of the present invention. In this figure, anormal CP is also taken as an example having a length of 14 OFDMsymbols. However, the difference between TDD system and the above FDDsystem is in that the primary synchronization signal is not in subframe0 and subframe 5 but in DwPTS of subframe 1 and subframe 6. For TDDsystem, the number of OFDM symbols L_(P-PRB) available in subframe 0,subframe 5 and subframe 6, as well as the number of OFDM symbolsN_(symbol,P-PRB) corresponding to punctured PRB after considering theoverhead for controlling signalling and pilot are listed as follows:

TABLE 6 a list of the number of symbols N_(symbol,P-PRB) correspondingto punctured PRB in TDD system Number of available Type OFDM symbolsL_(P-PRB) N_(symbol,P-PRB) normal CP subframe 0 9 5 subframe 5 13 9subframe 6 13 9 extended subframe 0 7 5 CP subframe 5 11 9 subframe 6 1193. Punctured PRB Caused by Sounding Reference Signaling (SRS)

If uplink subframe is configured to transmit SRS, the last OFDM symbolin PRB of PUSCH will be punctured. However, as only one OFDM symbol islost in this instance instead of more OFDM symbols being lost in theabove two instances, redundant descriptions will not be repeated in thepresent invention. However, a person skilled in the art could solve theproblem of punctured PRB caused by SRS according to the processing tothe above two instances proposed by the present invention.

It can be seen from the above listed instances in which punctured PRB isproduced that, as the punctured PRB will lost more OFDM symbols which iscaused by the influence of the length configuration of DwPTS as well asthe broadcast and synchronization channel, the system is correspondinglyinfluenced. Therefore, in one preferred embodiment of the presentinvention, the conversion is performed only taking the above twoinstances of producing punctured PRB into consideration for the sake ofefficiency. But it should be understood that the solution proposed inthe embodiments of the present invention are also applicable to otherinstances in which punctured PRB is produced. As there are many otherinstances in which punctured PRB is produced, redundant descriptionswill not be repeated herein.

In one embodiment of the present invention, the punctured PRB caused bythe length configuration of DwPTS as well as the broadcast andsynchronization channel is generalized. Table 7 can be obtained asfollows by combining tables 4, 5, 6 according to the number of symbol ofpunctured PRB without considering the difference of pilot overheadcaused by puncturing different symbols.

Number of available OFDM symbols L_(P-PRB) normal Extended RE numberType CP CP N_(symbol,P-PRB) N_(RE,P-PRB) 1 13 11 9 108 2 12 10 8 96 3 119 7 84 4 10 8 6 72 5 9 7 5 60 6 8 6 4 48

According to table 7, under the same MCS condition, the ratio of thenumber of normal PRB pairs to the number of punctured PRB pairs duringtransmission of some TBS is

$\frac{N_{PRB}}{N_{P - {PRB}}} \approx \frac{N_{{RE},{P - {PRB}}}}{120} \approx {\frac{N_{{symbol},{P - {PRB}}}}{10}.}$This formula is obtained in combination with the provisions of the sizeof the normal PRB in the protocol. As mentioned in the description onTable 2, the size of the normal PRB pairs is 120 REs or 10 OFDM symbols.

It is only one preferred embodiment of the present invention to combinetables 4, 5, 6 to obtain the table 7, and to obtain the conversionrelationship between the normal PRB pairs N_(PRB) and the punctured PRBpairs N_(P-PRB) according to table 7.

In one embodiment of the present invention, the conversion relationshipbetween the number of normal PRB pairs and the number of punctured PRBpairs is determined mainly based on the size of punctured PRB. The aboveformula is only one preferred embodiment of the present invention withthe assumption that the size of the normal PRB pairs is 120 REs or 10OFDM symbols. However, the present invention proposes a more universalconversion relationship, which is determined by the formula of spectrumefficiency

$\frac{TBS}{N_{P - {PRB}} \times N_{{RE},{P - {PRB}}}} \approx {\frac{TBS}{N_{PRB} \times N_{{RE},{PRB}}}\mspace{14mu}{or}}$${\frac{TBS}{N_{P - {PRB}} \times N_{{symbol},{P - {PRB}}}} \approx \frac{TBS}{N_{PRB} \times N_{{symbol},{PRB}}}},$wherein TBS is the size of carrying data blocks; N_(P-PRB) is the numberof punctured PRB pairs necessary for carrying the TBS; N_(PRB) is thenumber of normal PRB pairs necessary for carrying the TBS;N_(symbol,P-PRB) is the number of OFDM symbols in each pair of puncturedPRBs for carrying the TBS; N_(symbol,PRB) is the number of OFDM symbolsin each pair of normal PRBs for carrying the TBS; N_(RE,P-PRB) is thenumber of REs occupied by the punctured PRB; N_(RE,PRB) is the number ofREs occupied by the normal PRB. Furthermore, according to the aboveformula, the conversion relationship between the number of normal PRBpairs and the number of punctured PRB pairs can be determined by theformula of

$\frac{N_{PRB}}{N_{P - {PRB}}} \approx \frac{N_{{RE},{P - {PRB}}}}{N_{{RE},{PRB}}} \approx {\frac{N_{{symbol},{P - {PRB}}}}{N_{{symbol},{PRB}}}.}$

In one embodiment of the present invention, the conversion relationshipbetween the number of normal PRB pairs and the number of punctured PRBpairs can also be determined by

${N_{PRB} = \left\lfloor \frac{N_{P - {PRB}} \times N_{{symbol},{P - {PRB}}}}{N_{{symbol},{PRB}}} \right\rfloor},$wherein └x┘ means performing a rounding-down operation to x.

In one embodiment of the present invention, N_(symbol,PRB) is preferably10, N_(RE,P-PRB) is preferably 120 in the above formula. The presentinvention proposes three solutions of calculation means forN_(symbol,P-PRB) or N_(RE,P-PRB).

Solution 1:

N_(symbol,P-PRB) or N_(RE,P-PRB) can be obtained by looking up table 7according to the number of OFDM symbols available for punctured PRBpairs.

Solution 2:

N_(symbol,P-PRB) is determined by the formulaN_(symbol,P-PR)=L_(symbol,P-PRB)−k, wherein L_(symbol,P-PRB) ⁻represents the number of OFDM symbols available for punctured PRB pairs,and k is a constant related to the length of CP. In one embodiment ofthe present invention, k=4 for normal CP; and k=2 for extended CP.

Solution 3:

This solution is a way of simplification. If the size of punctured PRBpairs is smaller than some threshold value, then the number of symbolsof punctured PRB pairs is set to a predetermined value. For example, ifthe size of punctured PRB pairs is smaller than threshold value k₀, thenit is defaulted that the number of symbols of punctured PRB pairs isconstant k₁, wherein k₀, k₁ are constant. In one embodiment of thepresent invention, it is k₀=12, k₁=5 for normal CP and k₀=10, k₁=5 forextended CP.

Certainly, a person skilled in the art could also find other formulaeaccording to other principles under the same MCS conditions or use othersimilar means to determine the conversion relationship between thenumber of normal PRB pairs and the number of punctured PRB pairs. Thespecific conversion relationship can be simplified according to thenumber of OFDM symbols. For example, if 1 or 2 OFDM symbols arepunctured, then it is processed as a normal PRB; if 3 or 4 OFDM symbolsare punctured, then it is processed as the punctured PRB pairs having 7OFDM symbols; if 5 or more OFDM symbols are punctured, then it isprocessed as punctured PRB pairs having 5 OFDM symbols. Thus it shouldalso be noticed that there are many ways to determine the conversionrelationship between the number of normal PRB pairs N_(PRB) and thenumber of punctured PRB pairs N_(P-PRB), and the present invention onlyproposes a preferred embodiment and is not limited to this solution.Other conversion solutions based on the main concept of the presentinvention should be covered by the scope of protection of the presentinvention.

Embodiment 1

FIG. 6 is a flowchart of an adaptive modulation and coding methodaccording to embodiment 1 of the present invention, in which it is onlyconsidered that NodeB selects specific service subframes to transmitdownlink data for the UE. As the instance that NodeB selects generalservice subframes for the UE is the same as in the prior art, redundantdescriptions will not be repeated herein. This method includes thefollowing steps:

S601, the NodeB selects specific service subframes for the UE totransmit downlink data based on matters such as transmission quality.The PRB in the specific service subframes is the punctured PRB and thesize of its punctured PRB is related to the specific service subframes.The specific service subframes are e.g. subframe 0, subframe 5 in FDDsystem, subframe 0, subframe 5 and subframe 6 in TDD system etc.Furthermore, due to the difference among the specific service subframes,the sizes of punctured PRBs thereof are different either. For example,referring to tables 5 and 6, the punctured PRB in the subframe 0 of FDDsystem contains 4 OFDM symbols, and the punctured PRB in the subframe 0of TDD system contains 4 OFDM symbols. Certainly, the specific servicesubframes in LTE system are not limited to subframe 0, subframe 5 in FDDsystem and subframe 0, subframe 5 and subframe 6 in TDD system, butother subframes. For convenience of description, only the abovesubframes are used as examples in the following embodiments, and thesizes of their corresponding punctured PRB may refer to tables 5 and 6.

S602, the NodeB determines the size of TBS and the number of puncturedPRB pairs N_(P-PRB) to be transmitted based on the carried service. Theway for determining the size of TBS to be transmitted are differentdepending upon different carried services.

For VoIP service, as an example, its transmitted TBS has a constant sizeand cannot be divided, thus it is required to determine the size of TBSaccording to the carried service, and further to determine the optimumnumber of normal PRB pairs N_(PRB) based on the size of TBS as well asthe channel quality information. Then, the number of punctured PRB pairsN_(P-PRB) is obtained by converting the number of normal PRB pairsN_(PRB) accordingly. Wherein, the conversion relationship betweenN_(PRB) and N_(P-PRB) can be determined according to the size ofpunctured PRB, and can also be determined based on simplificationprocessing, or based on the formula of

$\frac{N_{PRB}}{N_{P - {PRB}}} \approx \frac{N_{{RE},{P - {PRB}}}}{120} \approx {\frac{N_{{symbol},{P - {PRB}}}}{10}\mspace{14mu}{or}}$$N_{PRB} = \left\lfloor \frac{N_{P - {PRB}}N_{{symbol},{P - {PRB}}}}{N_{{symbol},{PRB}}} \right\rfloor$as a preferred embodiment of the present invention.

However, for the data service, its entire data for transmission is huge,thus it needs to be divided according to the TBS that can be carried ineach transmission. The NodeB selects the size of TBS based on channelquality information and the schedulable resource. After the NodeBselects the number of punctured PRB pairs N_(P-PRB) based on theschedulable resource, the number of punctured PRB pairs N_(P-PRB) isconverted so as to obtain the number of normal PRB pairs N_(PRB)accordingly. Finally, TBS is obtained by looking up the existing TBStable according to the number of normal PRB pairs N_(PRB).

S603, the NodeB schedules the downlink data for UE based on thedetermined size of TBS, and schedules N_(P-PRB) punctured PRB pairs forthe UE in the scheduling signalling, and informs the UE of the number ofthe used punctured PRB pairs N_(P-PRB).

S604, the UE receives the downlink data transmitted from the NodeB, andobtains the MCS sequence number I_(MCS) indicated by the schedulesignalling and the number of punctured PRB pairs N_(P-PRB) in theschedule signalling.

S605, the UE could know from the system information whether the NodeBtransmits downlink data by the specific service subframes, and therebythe UE performs reverse conversion on the obtained number of puncturedPRB pairs N_(P-PRB), and determines the corresponding number of normalPRB pairs N_(PRB). Similarly, the conversion relationship betweenN_(PRB) and N_(P-PRB) can be determined according to the size ofpunctured PRB, and can also be determined based on simplificationprocessing, or based on the formula of

$\frac{N_{PRB}}{N_{P - {PRB}}} \approx \frac{N_{{RE},{P - {PRB}}}}{120} \approx {\frac{N_{{symbol},{P - {PRB}}}}{10}\mspace{14mu}{or}}$$N_{PRB} = \left\lfloor \frac{N_{P - {PRB}}N_{{symbol},{P - {PRB}}}}{N_{{symbol},{PRB}}} \right\rfloor$as a preferred embodiment of the present invention.

S606, the UE determines the modulation scheme Q_(m) and the TBS sequencenumber I_(TBS) (see table 1) based on the MCS sequence number I_(MCS),and then looks up the TBS table to determine the TBS of downlink databased on the TBS sequence number I_(TBS) and the converted number of thenormal PRB pairs N_(PRB).

In one embodiment of the above the method, when the code word is mappedto an n-layer spatial multiplexing (n is positive integer), the numberof the punctured PRB pairs and the number of the normal PRB pairs aremultiplied by n. For example, as to the mode of mapping one code word toa 2-layer spatial multiplexing, the above N_(RE,P-PRB) orN_(symbol,P-PRB) are replaced by 2*N_(RE,P-PRB) or 2*N_(symbol,P-PRB).

FIG. 7 is a structural view of an adaptive modulation and coding systemaccording to one embodiment of the present invention. The systemincludes a NodeB 100 and at least one UE 200 being served by this NodeB100. The NodeB 100 selects specific service subframes, in which thephysical block PRB is the punctured PRB, for the UE 200 to transmitdownlink data, and schedules the downlink data for the UE 200 based onthe determined TBS, and then transmits the number of the used puncturedPRB pairs and a MCS sequence number to the UE 200; the UE 200 is usedfor receiving the downlink data transmitted by the NodeB 100 and thenumber of the used punctured PRB pairs and the MCS sequence numbertransmitted by the NodeB, and converting the received number of thepunctured PRB pairs to the number of normal PRB pairs, as well asdetermining the modulation and coding scheme MCS based on the number ofthe normal PRB pairs and the MCS sequence number.

In one embodiment of the present invention, the NodeB 100 comprises aselection module 110, a scheduling parameter determination module 120,and a scheduling module 130. The selection module 110 is used forselecting specific service subframes, in which the physical block PRB isthe punctured PRB, for the UE 200 to transmit the downlink data. Thescheduling parameter determination module 120 is used for determiningthe Transport Block Size TBS and the number of punctured PRB pairs fortransmission to the UE 200 based on the carried service. The schedulingmodule 130 is used for scheduling the downlink data for the UE 200 basedon the determined TBS, and then transmitting the number of the usedpunctured PRB pairs and a MCS sequence number to the UE 200.

In one embodiment of the present invention, the scheduling parameterdetermination module 120 includes a service judgement submodule 121, aconversion submodule 122, a TBS determination submodule 123 and acontrol submodule 124. The service judgement submodule 121 is used forjudging the carried service is VoIP service or data service. Theconversion submodule 122 is used for realizing the conversion betweenthe number of the normal PRB pairs to the number of punctured PRB pairs.The TBS determination submodule 123 is used for determining the TBSbased on the carried service upon the service judgement submodule 121judged the carried service as VoIP service, and based on the number ofthe normal PRB pairs converted by the conversion submodule 122 upon theservice judgement submodule 121 judged the carried service as dataservice. The control submodule 124 is used for firstly determining theTBS based on the carried service by the TBS determination submodule 123upon the service judgement submodule 121 has judged the carried serviceas VoIP service, and determining the number of the normal PRB pairsbased on the TBS determined by the TBS determination submodule 123 andchannel quality information, and then obtaining the number of puncturedPRB pairs by converting the number of the normal PRB pairs by theconversion submodule 122. Furthermore, the control submodule is alsoused for firstly determining the number of the punctured PRB pairs basedon the schedulable resource upon the service judgement submodule 121 hasjudged the carried service as data service, and obtaining the number ofnormal PRB pairs by converting the number of punctured PRB pairs by theconversion module 122, and then obtaining TBS by looking up tables withthe TBS module 123 according to the number of normal PRB pairs.

In one embodiment of the present invention, the conversion module 122determines the conversion relationship between the number of normal PRBpairs and the number of punctured PRB pairs according to the size ofpunctured PRB or the simplification processing. In the above embodiment,the conversion module 122 determines the conversion relationship betweenthe number of normal PRB pairs and the number of punctured PRB pairsbased on the formula of

$\frac{N_{PRB}}{N_{P - {PRB}}} \approx \frac{N_{{RE},{P - {PRB}}}}{120} \approx {\frac{N_{{symbol},{P - {PRB}}}}{10}\mspace{14mu}{or}}$${N_{PRB} = \left\lfloor \frac{N_{P - {PRB}}N_{{symbol},{P - {PRB}}}}{N_{{symbol},{PRB}}} \right\rfloor},$wherein N_(P-PRB) is the number of punctured PRB pairs, N_(PRB) is thenumber of normal PRB pairs, N_(symbol,P-PRB) represents the number oforthogonal frequency division multiplexing OFDM symbols occupied bypunctured PRB, and N_(RE,P-PRB) represents the number of REs occupied bypunctured PRB.

In the above embodiment, the NodeB 100 further includes a multiplexingmodule 140 for multiplying the number of punctured PRB pairs and thenumber of normal PRB pairs by n (n is positive integer) when the codeword is mapped to an n-layer spatial multiplexing.

In one embodiment of the present invention, the UE 200 comprises areception module 210, an indication information obtaining module 220, aconversion module 230 and a TBS determination module 240. The receptionmodule 210 is used for receiving the downlink data transmitted throughspecific service subframes by the NodeB 100. The indication informationobtaining module 220 is used for obtaining the number of the puncturedPRB pairs and the MCS sequence number indicated by the schedulingsignalling. The conversion module 230 is used for converting the numberof the punctured PRB pairs to the number of normal PRB pairs. The TBSdetermination module 240 is used for determining the TBS of the downlinkdata based on the number of the normal PRB pairs converted by theconversion module and the MCS sequence number obtained by the indicationinformation obtaining module.

In one embodiment of the present invention, The TBS determination module240 includes a table save submodule 241 and a looking-up-table submodule242. The table save submodule 241 is used for saving the list of themodulation scheme corresponding to the MCS sequence number and the listof the TBS sequence number as well as TBS tables, such as the abovetables 1 and 2. The looking-up-table submodule 242 is used fordetermining the modulation scheme and TBS sequence number according tothe MCS sequence number obtained by the indication information obtainingmodule 220, and then determining the TBS of the downlink data based onthe number of the normal PRB pairs converted by the conversion module230 and the TBS sequence number.

In one embodiment of the present invention, the conversion module 230determines the conversion relationship between the number of normal PRBpairs and the number of punctured PRB pairs according to the size ofpunctured PRB or the simplification processing.

In the above embodiment, the conversion module 230 determines theconversion relationship between the number of normal PRB pairs and thenumber of punctured PRB pairs based on the formula of

$\frac{N_{PRB}}{N_{P - {PRB}}} \approx \frac{N_{{RE},{P - {PRB}}}}{120} \approx {\frac{N_{{symbol},{P - {PRB}}}}{10}\mspace{14mu}{or}}$${N_{PRB} = \left\lfloor \frac{N_{P - {PRB}}N_{{symbol},{P - {PRB}}}}{N_{{symbol},{PRB}}} \right\rfloor},$wherein N_(P-PRB) is the number of punctured PRB pairs, N_(PRB) is thenumber of normal PRB pairs, N_(symbol,P-PRB) represents the number ofOFDM symbols occupied by the punctured PRB, N_(RE,P-PRB) represents thenumber of REs occupied by the punctured PRB. In the above embodiments ofthe UE and the NodeB, the conversion relationship between the number ofnormal PRB pairs and the number of punctured PRB pairs is similar to theconversion relationship in the above embodiments, and redundantdescriptions will not be repeated.

The specific condition when downlink data are transmitted with puncturedPRBs may be performed in the present invention on the basis of utilizingthe existing resources and adaptive processing of the general subframesby performing conversion between the number of punctured PRBs and thenumber of normal PRBs in scheduling resource for the UE with the NodeB,which may be implemented simply and efficiently.

The above embodiments are all the embodiments for the instances oftransmitting downlink data with punctured PRBs, but there are alsoinstances of transmitting downlink data with both normal and puncturedPRBs by NodeB. Based on the above, the present invention also proposesan adaptive modulation and coding method and apparatus when downlinkdata are transmitted with both normal and punctured PRBs.

Embodiment 2

FIG. 8 is a flowchart of an adaptive modulation and coding methodaccording to the embodiment 2 of the present invention, and the methodincludes the following steps:

S801 The NodeB selects punctured PRB and normal PRB for the UE totransmit downlink data. In one embodiment of the present invention, eachnormal PRB pair contains 120 REs for carrying data, wherein 120 REs areequivalent to 10 OFDM symbols. Punctured PRB may be caused by theinfluences of DwPTS's length configuration or broadcast andsynchronization channel. As described in the above embodiment, thenumber of OFDM symbols or REs are different in punctured PRBs caused bydifferent influences, redundant descriptions will not be repeated.

S802, the NodeB determines the TBS and the number of total PRB pairs tobe transmitted to UE based on the carried service. The number of totalPRB pairs is the summation of the number of the scheduled normal PRBpairs and the number of the scheduled punctured PRB pairs. The way fordetermining the size of TBS to be transmitted are different dependingupon different carried services.

For the service having a constant size of data packet (such as VoIPservice), as an example, the size of transmitted TBS is fixed and cannotbe divided, thus it is required to determine the size of TBS accordingto the carried service, and further to determine the specific number ofPRB pairs N_(PRB) for carrying this data block according to the size ofTBS as well as the channel quality information. Then the NodeB selectsnormal PRB and punctured PRB for the UE to transmit downlink dataaccording to the schedulable resource, namely the NodeB schedules a partof normal PRB (N_(PRB1)) for the UE, and also schedules a part ofpunctured PRB for the UE in which there may be various PRB pairs havingdifferent granularities. For example, punctured PRB caused by theinfluence of broadcast- and synchronization channel and/or punctured PRBcaused by the influence of DwPTS's length, or other punctured PRB may beused. Wherein, the number of punctured PRB pairs should be obtained byconversion, for example, for punctured PRB caused by the influence ofDwPTS's length, based onN _(P-PRB) =┌N _(PRB)×10/N _(symbol,P-PRB)┐ or N _(P-PRB) =┌N_(PRB)×120/N _(RE,P-PRB)┐, whereinN_(PRB) is the number of normal PRB pairs (except for the scheduled partof normal PRB (N_(PRB1)) for the UE), N_(P-PRB) is the number ofconverted punctured PRB pairs, N_(symbol,P-PRB) represents the number ofOFDM symbols occupied by punctured PRB, N_(RE,P-PRB) represents thenumber of RE occupied by punctured PRB. The number of the total PRBpairs is the summation of the scheduled part of normal PRB (N_(PRB1))for the UE and the number of converted punctured PRB pairs N_(P-PRB).

However, for the service having an unfixed size of data packet (such asdata service), its entire data for transmission is huge, thus it needsto be divided according to the TBS that can be carried in eachtransmission. The NodeB selects the size of TBS based on channel qualityinformation and the schedulable resource. Firstly, after the NodeBselects the number of scheduled normal PRB pairs and the number ofpunctured PRB pairs based on the schedulable resource, the NodeBcalculates number of the total PRB pairs as the summation of the normalPRB pairs and the number of punctured PRB pairs assuming that the NodeBschedules N_(PRB1) normal PRB pairs for the UE and schedules N_(P-PRB)punctured PRB pairs for the UE at the same time. The NodeB obtains thenumber of normal PRB pairs N_(PRB) by converting the number of puncturedPRB pairs, and then looks up the table according to the sum of N_(PRB1)and N_(PRB) to obtain TBS and schedules a data packet with a size of TBSto be transmitted on determined PRB. Specifically, the conversionrelationship between the normal PRB pairs and the punctured PRB pairscan be determined according to the size of punctured PRB. For example,it can be calculated based on the formula ofN _(PRB) =└N _(P-PRB) ×N _(symbol,P-PRB)/10┘ or N _(PRB) =└N _(P-PRB) ×N_(RE,P-PRB)/120┘.

S803, the NodeB schedules the downlink data for UE based on thedetermined TBS, and sends the number of the totally used PRB pairs,location information and the related system information to UE.

S804, the UE calculates the number of the total resource according tothe number of the total PRB pairs, location information and thesituation of respective punctured PRBs. In particular, UE may know whichPRB is punctured PRB and which PRB is normal PRB in the number of thetotal PRB pairs according to location information, and could calculatethe number of total resource quantity according to the situation ofrespective punctured PRBs. In one embodiment of the present invention,one code word is scheduled to be carried on various PRB pairs havingdifferent granularities resources, that is, various punctured PRBs arescheduled for the UE, in this way the total resource quantity can becalculated with the formula of

${\sum\limits_{i}{R_{i} \times N_{i}}},$wherein Ri is resource granularity of each kind of PRB, Ni is the numberof each kind of PRB, i=1, . . . n, n is the number of total PRB pairs,namely for normal PRB, Ri is 120 REs or 10 OFDM symbols; for puncturedPRB, Ri is variable, i.e., as the above the, Ri will vary according tothe different influences leading to punctured PRB.

In one embodiment of the present invention, for the sake ofsimplification, the resource with the minimum resource granularity maybe determined in PRB resources having various granularities, and thenumber of total resource may be converted according to the instance ofminimum PRB. For example, the number of total resource can be obtainedaccording to the formula R_(min)×N_(PRB), wherein R_(min) is theresource granularity of PRB having the minimum granularity, N_(PRB) isthe number of the total PRB pairs. Although the preciseness issacrificed in this way, the calculation is simplified greatly. It can beseen from the above description that the number of total resource can becalculated with various means without departing from the concept of thepresent invention, and other similar methods should also fall in thescope of protection of the present invention.

S805 The UE calculates the number of normal PRB pairs after conversionaccording to the number of total resource, and determines the TBS ofdownlink data based on the calculated number of normal PRB pairs afterconversion and the TBS sequence number based on the MCS sequence number.In particular, in one embodiment of the present invention, if the numberof total resource is

${\sum\limits_{i}{R_{i} \times N_{i}}},$then the number of normal PRB pairs after conversion may be

${N_{PRB}^{\prime} = \left\lfloor \frac{\sum\limits_{i}{R_{i} \times N_{i}}}{R_{0}} \right\rfloor},$wherein R₀ is the resource number of general PRB pairs, and thecorresponding LTE system can be considered to have 12 OFDM symbols or120 REs, N′_(PRB) is the number of normal PRB pairs after conversion,└x┘ means performing a rounding-down operation to x. Then the TBS ofdownlink data is determined by looking up MCS table based on the numberof normal PRB pairs after conversion. In one embodiment of the presentinvention, in order to avoid the value of N′_(PRB) i to be 0, the numberof normal PRB pairs after conversion may also be

$N_{PRB}^{\prime} = {\max{\left\{ {1,\left\lfloor \frac{\sum\limits_{i}{R_{i} \times N_{i}}}{R_{0}} \right\rfloor} \right\}.}}$

In the simplification processing in the above embodiment, the number ofnormal PRB pairs after conversion may also be

${N_{PRB}^{\prime} = {\max\left\{ {1,\left\lfloor \frac{R_{\min} \times N_{PRB}}{R_{0}} \right\rfloor} \right\}}},$wherein R_(min) is the resource quantity of PRB having the minimumgranularity, N_(PRB) is the number of the total PRB pairs, N′_(PRB) isthe number of normal PRB pairs after conversion, └x┘ means performing arounding-down operation to x.

Of course in the embodiments of the present invention, the number ofnormal PRB pairs after conversion may also be calculated with othermeans, e.g., with the formula Np+N′_(PRB), wherein Np is the number ofnormal PRB pairs (i.e., N_(PRB1) in the above embodiment),

${N_{PRB}^{\prime} = {\max\left\{ {1,\left\lfloor \frac{\sum\limits_{i}{R_{i} \times N_{i}}}{R_{0}} \right\rfloor} \right\}}},$Ri is the resource granularity of punctured PRB, and Ni is the number ofpunctured PRB.

Certainly, the above examples on how to calculate the number of normalPRB pairs after conversion are only embodiments of the presentinvention, and a person skilled in the art could perform equivalentcalculations according to the above embodiments of the presentinvention. These equivalent calculations based on the identicalinventive concept should be covered by the scope of protection of thepresent invention.

FIG. 9 is a structural view of an adaptive modulation and coding systemaccording to one embodiment of the present invention. The systemincludes a NodeB 800 and at least one UE 900 being served by this NodeB800. The NodeB 800 selects normal PRB and punctured PRB to transmit thedownlink data for the UE 900, and determines the TBS and the number oftotal PRB pairs for transmission to the UE 900 based on the carriedservice, in which the number of total PRB pairs is the summation of thenumber of the scheduled normal PRB pairs and the number of the scheduledpunctured PRB pairs, and schedules the downlink data for the UE 900based on the determined TBS, and transmits the number of the total usedPRB pairs and a MCS sequence number to the UE 900. The UE 900 is usedfor calculating the number of total resource based on the number of thetotal PRB pairs and situation of respective punctured PRBs, andcalculating the number normal PRB pairs after conversion based on thetotal resource quantity, and determining the TBS of the downlink databased on the calculated number of the normal PRB pairs after conversionand the TBS sequence number determined by the MCS sequence number.

Wherein, the NodeB 800 comprises a selection module 810, a schedulingparameter determination module 820, and a scheduling module 830. Theselection module 810 is used for selecting punctured PRB and normal PRBfor the UE 900 to transmit the downlink data. The scheduling parameterdetermination module 820 is used for determining the Transport BlockSize TBS and the number of the total PRB pairs for transmission to theUE 900 based on the carried service. The number of the total PRB pairsis the summation of the number of the scheduled normal PRB pairs and thenumber of the scheduled punctured PRB pairs. The scheduling module 830is used for scheduling to transmit the downlink data for the UE 900based on the determined TBS, and then transmitting the number of thetotal used PRB pairs and the MCS sequence number to the UE 900.

If the service carried by the NodeB 800 is VoIP service, the schedulingparameter determination module 820 determines the TBS based on the VoIPservice, and determines the number of normal PRB pairs based on thedetermined TBS and channel quality information, and selects normal PRBand punctured PRB for the UE 900 to transmit the downlink data accordingto the schedulable resource, and calculates the number of punctured PRBpairs as well as the number of the total PRB pairs, wherein the numberof punctured PRB pairs is obtained by converting the number of normalPRB pairs.

If the service carried by the NodeB 800 is data service, the schedulingparameter determination module 820 determines the number of schedulednormal PRB pairs and the number of punctured PRB pairs according to theschedulable resource, and calculates the number of the total PRB pairsas a summation of the number of normal PRB pairs and the number ofpunctured PRB pairs, and obtains the number of normal PRB pairs afterconversion by converting the number of punctured PRB pairs. And TBS isobtained by looking up tables according to the number of normal PRBpairs and the number of normal PRB pairs after conversion.

In one embodiment of the present invention, the conversion relationshipbetween the number of normal PRB pairs and the number of punctured PRBpairs is determined according to the size of punctured PRB.

In the above the embodiment, the UE 900 comprises a reception module910, an indication information obtaining module 920, a normal PRBpair-number calculation module 930 and a TBS determination module 940.The reception module 910 is used for receiving the downlink datatransmitted through the punctured and normal PRBs by the NodeB 800. Theindication information obtaining module 920 is used for acquiring theMCS sequence number and the number of the total PRB pairs indicated bythe scheduling signalling, wherein the number of the total PRB pairs isthe summation of the number of the scheduled normal PRB pairs and thenumber of the punctured PRB pairs. The normal PRB pair-numbercalculation module 930 is used for calculating the total resourcequantity based on the number of the total PRB pairs and the situation ofrespective punctured PRBs, and calculating the number of the normal PRBpairs after conversion based on the total resource quantity. The TBSdetermination module 940 is used for determining the TBS of the downlinkdata based on the calculated number of the normal PRB pairs afterconversion and the TBS sequence number determined by the MCS sequencenumber.

In one embodiment of the present invention, the normal PRB pair-numbercalculation module 930 determines the number of total resource with theformula of

${\sum\limits_{i}{R_{i} \times N_{i}}},$wherein Ri is resource granularity of each kind of PRB, Ni is the numberof each kind of PRB. Then the number of normal PRB pairs afterconversion may be calculated with the formula of

${N_{PRB}^{\prime} = {{\left\lfloor \frac{\sum\limits_{i}{R_{i} \times N_{i}}}{R_{0}} \right\rfloor\mspace{14mu}{or}\mspace{14mu} N_{PRB}^{\prime}} = {\max\left\{ {1,\left\lfloor \frac{\sum\limits_{i}{R_{i} \times N_{i}}}{R_{0}} \right\rfloor} \right\}}}},$wherein N′_(PRB) is the number of normal PRB pairs after conversion, └x┘means performing a rounding-down operation to x.

In another embodiment of the present invention, the normal PRBpair-number calculation module 930 determines the number of totalresource with the formula R_(min)×N_(PRB), wherein R_(min) is theresource quantity of PRB having the minimum granularity, N_(PRB) is thenumber of the total PRB pairs; then the number of normal PRB pairs afterconversion is calculated with the formula

${N_{PRB}^{\prime} = {\max\left\{ {1,\left\lfloor \frac{R_{\min} \times N_{PRB}}{R_{0}} \right\rfloor} \right\}}},$wherein R_(min) is the resource quantity of PRB having the minimumgranularity, N_(PRB) is the number of the total PRB pairs.

In another embodiment of the present invention, the normal PRBpair-number calculation module 930 determines the number of normal PRBpairs after conversion with the formula Np+N′_(PRB), wherein Np is thenumber of normal PRB pairs,

${N_{PRB}^{\prime} = {\max\left\{ {1,\left\lfloor \frac{\sum\limits_{i}{R_{i} \times N_{i}}}{R_{0}} \right\rfloor} \right\}}},$Ri is the resource granularity of punctured PRB, and Ni is the number ofpunctured PRB.

The specific condition when downlink data are transmitted completely forpartly with punctured PRBs may be performed in the present invention onthe basis of utilizing the existing resources and adaptive processing ofthe general subframes by performing the present invention, which may beimplemented simply and efficiently.

Although the embodiments of the present invention have been shown anddescribed in the above, a person skilled in the art could subject theseembodiments to various variations, modifications, substitutions andtransformations without departing from the principle and spirit of thepresent invention, and the scope of protection of the present inventionis defined by the appended claims and equivalents thereof.

The invention claimed is:
 1. An adaptive modulation and coding method,comprising the following steps: a transmitting node selects puncturedPRBs and normal PRBs to transmit downlink data; the transmitting nodedetermines a Transport Block Size TBS and the number of total PRB pairsfor transmission to a receiving node based on a carried service, thenumber of total PRB pairs being the summation of the number of thescheduled normal PRB pairs and the number of the punctured PRB pairs;the transmitting node schedules the downlink data for the receiving nodebased on the determined TBS, and transmits the number of the total usedPRB pairs, location information and a Modulation and Coding Scheme MCSsequence number to the receiving node; the receiving node calculates thenumber of total resource based on the number of the total PRB pairs, thelocation information and the situation of each punctured PRB; thereceiving node calculates the number of the normal PRB pairs afterconversion based on the number of total resource, determines the TBS ofthe downlink data based on the calculated number of the normal PRB pairsafter conversion and the TBS sequence number determined by the MCSsequence number.
 2. The adaptive modulation and coding method as claimedin claim 1, wherein, when the service carried by the transmitting nodeis a service of data packet having a fixed size, the step of thetransmitting node determining the TBS and the number of total PRB pairsfor transmission to the receiving node based on the carried service, thenumber of total PRB pairs being the summation of the number of thescheduled normal PRB pairs and the number of the punctured PRB pairs,includes the following steps: the transmitting node determines the TBSbased on the carried service; the transmitting node determines thenumber of the PRB pairs carrying the data block according to thedetermined TBS and channel quality information; the transmitting nodeselects the normal PRB and the punctured PRB for the receiving node totransmit the downlink data based on a schedulable resource, andcalculates the number of the punctured PRB pairs and the number of thetotal PRB pairs, wherein the number of the punctured PRB pairs isobtained by converting the number of the normal PRB pairs.
 3. Theadaptive modulation and coding method as claimed in claim 1, wherein,when the service carried by the transmitting node is a service of datapacket having an unfixed size, the step of the transmitting nodedetermining the TBS and the number of total PRB pairs for transmissionto the receiving node based on the carried service, the number of totalPRB pairs being the summation of the number of the scheduled normal PRBpairs and the number of the punctured PRB pairs, includes the followingsteps: the transmitting node determines the number of the schedulednormal PRB pairs and the number of the punctured PRB pairs based on aschedulable resource; the transmitting node calculates the number of thetotal PRB pairs as the summation of the number of the normal PRB pairsand the number of the punctured PRB pairs; the transmitting node obtainsthe number of the normal PRB pairs after conversion by converting thenumber of the punctured PRB pairs; the transmitting node looks up thetable according to the number of the normal PRB pairs and the number ofthe normal PRB pairs after conversion to obtain the TBS and schedules adata packet with a size of TBS to transmit on determined PRBs.
 4. Theadaptive modulation and coding method as claimed in claim 1, wherein,the step of the receiving node calculating the number of total resourcebased on the number of the total PRB pairs and the situation of eachpunctured PRB includes: the number of total resource is calculated basedon the following formula of: ${\sum\limits_{i}{R_{i} \times N_{i}}},$wherein Ri is resource granularity of each kind of PRBs, Ni is thenumber of each kind of PRBs.
 5. The adaptive modulation and codingmethod as claimed in claim 4, wherein, the step of the receiving nodecalculating the number of the normal PRB pairs after conversion based onthe number of total resource includes: the number of the normal PRBpairs after conversion is calculated based on the following formula of:${N_{PRB}^{\prime} = {{\left\lfloor \frac{\sum\limits_{i}{R_{i} \times N_{i}}}{R_{0}} \right\rfloor\mspace{14mu}{or}\mspace{14mu} N_{PRB}^{\prime}} = {\max\left\{ {1,\left\lfloor \frac{\sum\limits_{i}{R_{i} \times N_{i}}}{R_{0}} \right\rfloor} \right\}}}},$wherein N′_(PBR) is the number of the normal PRB pairs after conversion,└x┘ represents performing a rounding-down operation to x.
 6. Theadaptive modulation and coding method as claimed in claim 1, wherein,the step of the receiving node calculating the number of total resourcebased on the number of the total PRB pairs and the situation of eachpunctured PRBs includes: the number of total resource is calculatedbased on the following formula of: R_(min)×N_(PRB), wherein R_(min) isthe resource granularity of PRB having the minimum granularity, N_(PRB)is the number of the total PRB pairs.
 7. The adaptive modulation andcoding method as claimed in claim 6, wherein, the step of the receivingnode calculating the number of the normal PRB pairs after conversionbased on the number of total resource includes: the number of the normalPRB pairs after conversion is calculated based on the following formulaof:${N_{PRB}^{\prime} = {\max\left\{ {1,\left\lfloor \frac{R_{\min} \times N_{PRB}}{R_{0}} \right\rfloor} \right\}}},$wherein R_(min) is the resource granularity of PRB having the minimumgranularity, N_(PRB) is the number of the total PRB pairs.
 8. Theadaptive modulation and coding method as claimed in claim 1, wherein,the step of calculating the number of the normal PRB pairs afterconversion includes: the number of the normal PRB pairs after conversionis Np+N′_(PRB), wherein Np is the number of the normal PRB pairs,${N_{PRB}^{\prime} = {\max\left\{ {1,\left\lfloor \frac{\sum\limits_{i}{R_{i} \times N_{i}}}{R_{0}} \right\rfloor} \right\}}},$Ri is the resource granularity of the punctured PRB, and Ni is thenumber of the punctured PRB.
 9. The adaptive modulation and codingmethod as claimed in claim 1, wherein, the number of the schedulednormal PRB pairs is zero.
 10. The adaptive modulation and coding methodas claimed in claim 9, wherein, when the service carried by thetransmitting node is VoIP service, the step of determining the TransportBlock Size TBS and the number of total PRB pairs for transmission to thereceiving node further includes the following steps: the transmittingnode determines the TBS based on the carried service; the transmittingnode determines the number of the normal PRB pairs based on thedetermined TBS and channel quality information; the transmitting nodeNodeB obtains the number of the punctured PRB pairs by converting thenumber of the normal PRB pairs.
 11. The adaptive modulation and codingmethod as claimed in claim 9, wherein, when the service carried by thetransmitting node is data service, the step of determining the TransportBlock Size TBS and the number of total PRB for transmission to thereceiving node further includes the following steps: the transmittingnode determines the number of the punctured PRB pairs based on aschedulable resource; the transmitting node obtains the number of thenormal PRB pairs by converting the number of the punctured PRB pairs;the transmitting node obtains the TBS by looking up tables according tothe number of the normal PRB pairs.
 12. The adaptive modulation andcoding method as claimed in claim 9, wherein, the conversionrelationship between the number of the normal PRB pairs and the numberof the punctured PRB pairs is determined based on the size of thepunctured PRB.
 13. The adaptive modulation and coding method as claimedin claim 12, wherein, the conversion relationship between the number ofthe normal PRB pairs and the number of the punctured PRB pairs isdetermined based on the size of the punctured PRB, that is: based on aspectrum efficiency formula of$\frac{TBS}{N_{P\text{-}{PRB}} \times N_{{RE},{P\text{-}{PRB}}}} \approx {\frac{TBS}{N_{PRB} \times N_{{RE},{PRB}}}\mspace{14mu}{or}}$${\frac{TBS}{N_{P{\text{-}\text{PRB}}} \times N_{{symbol},{P\text{-}{PRB}}}} \approx \frac{TBS}{N_{PRB} \times N_{{symbol},{PRB}}}},$wherein the TBS is the size of the carried data block; N_(P-PRB) is thenumber of the punctured PRB pairs for carrying the TBS, N_(PRB) is thenumber of the normal PRB pairs for carrying the TBS; N_(symbol,P-PRB) isthe number of Orthogonal Frequency Division Multiplexing OFDM symbols ineach pair of the punctured PRB for carrying the TBS, N_(symbol,PRB) isthe number of Orthogonal Frequency Division Multiplexing OFDM symbols ineach pair of the normal PRB for carrying the TBS; N_(RE,P-PRB) is thenumber of REs occupied by the punctured PRB, N_(RE,PRB) is the number ofREs occupied by the normal PRB.
 14. The adaptive modulation and codingmethod as claimed in claim 13, wherein, the conversion relationshipbetween the number of the normal PRB pairs and the number of thepunctured PRB pairs is determined based on the formula of$\frac{N_{PRB}}{N_{P\text{-}{PRB}}} \approx \frac{N_{{RE},{P\text{-}{PRB}}}}{N_{{RE},{PRB}}} \approx {\frac{N_{{symbol},{P\text{-}{PRB}}}}{N_{{symbol},{PRB}}}.}$15. The adaptive modulation and coding method as claimed in claim 12,wherein, the conversion relationship between the number of the normalPRB pairs and the number of the punctured PRB pairs is determined basedon a formula of${N_{PRB} = \left\lfloor \frac{N_{P\text{-}{PRB}}N_{{symbol},{P\text{-}{PRB}}}}{N_{{symbol},{PRB}}} \right\rfloor},$wherein └x┘ represents performing a rounding-down operation to x. 16.The adaptive modulation and coding method as claimed in claim 14,wherein, the N_(symbol,P-PRB) or N_(RE,P-PRB) is obtained by looking upthe following table according to the number of OFDM symbols availablefor the punctured PRB pairs: Number of OFDM symbols available for thepunctured PRB pairs normal extended Type CP CP N_(symbol,P-PRB)N_(RE,P-PRB) 1 13 11 9 108 2 12 10 8 96 3 11 9 7 84 4 10 8 6 72 5 9 7 560 6 8 6 4
 48.


17. The adaptive modulation and coding method as claimed in claim 14,wherein, the N_(symbol,P-PRB) is determined based on the formula ofN_(symbol,P-PRB)=L_(symbol,P-PRB)−k, wherein L_(P-PRB) represents thenumber of OFDM symbols available for the punctured PRB pairs, k is aconstant related to the length of the CP.
 18. The adaptive modulationand coding method as claimed in claim 17, wherein, for the normal CP,k=4; and for the extended CP, k=2.
 19. The adaptive modulation andcoding method as claimed in claim 14, wherein, the N_(symbol,P-PRB) isobtained as follows: If the size of the punctured PRB pairs is smallerthan a threshold value k₀, then it is defaulted that the number ofsymbols of the punctured PRB pairs is a constant k₁, wherein k₀, k₁ areconstant.
 20. The adaptive modulation and coding method as claimed inclaim 19, wherein, for the normal CP, k₀=12, k₁=5; and for the extendedCP, k₀=10, k₁=5.
 21. The adaptive modulation and coding method asclaimed in claim 9, wherein, when a code word is mapped to an n-layerspatial multiplexing (n is positive integer), the number of thepunctured PRB pairs and the number of the normal PRB pairs aremultiplied by n.
 22. An adaptive modulation and coding system,comprising a transmitting node and at least one receiving node served bythe transmitting node, wherein the transmitting node is used forselecting punctured PRBs and normal PRBs to transmit downlink data, anddetermining a Transport Block Size TBS and the number of total PRB pairsfor transmission to the receiving node based on a carried service, thenumber of total PRB pairs being the summation of the number of thescheduled normal PRB pairs and the number of the punctured PRB pairs;scheduling the downlink data for the receiving node based on thedetermined TBS, and transmitting the number of the total used PRB pairs,location information and a Modulation and Coding Scheme MCS sequencenumber to the receiving node; the receiving node is used for calculatingthe number of total resource based on the number of the total PRB pairs,the location information and the situation of each punctured PRB;calculating the number of the normal PRB pairs after conversion based onthe number of total resource, and determining the TBS of the downlinkdata based on the calculated number of the normal PRB pairs afterconversion and the TBS sequence number determined by the MCS sequencenumber.
 23. A receiving node, comprising a reception module, anindication information obtaining module, a normal PRB pair-numbercalculation module and a TBS determination module, wherein the receptionmodule is used for receiving downlink data transmitted through puncturedPRBs and normal PRBs by the transmitting node; the indicationinformation obtaining module is used for obtaining the MCS sequencenumber and the number of the total PRB pairs indicated by the schedulingsignalling, wherein the number of the total PRB pairs is the summationof the number of the scheduled normal PRB pairs and the number of thepunctured PRB pairs; the normal PRB pair-number calculation module isused for calculating the number of total resource based on the number ofthe total PRB pairs and the situation of each punctured PRB, andcalculating the number of the normal PRB pairs after conversion based onthe number of total resource; the TBS determination module is used fordetermining the TBS of the downlink data based on the calculated numberof the normal PRB pairs after conversion and the TBS sequence numberdetermined by the MCS sequence number.